My MD is a Zotac Ion, and that works with HDMI audio without an issue, always has. Its the New(ish) GT430 card in the core thats giving me the headache. I'm really hoping that somebody who knows the system can see why the AVWizard won't run with the newer Nvidia driver isntalled. Something about API Kernel mismatch, but all the info from google is based on standard Linux installations, and this doesn't apply with LMCE, so I'm a bit stuck at the moment.
I've tried a few suggestions that helped others out in the links you posted previously, no luck so far but I'm not giving up!! Must be a basic setting somewhere, but I'm patiently waiting for your experiments to provide the answer, as my tinkering hasn't yielded results.